The present invention relates to mixing valve, particularly mixing valves for kitchen or bath sinks, showerheads, tub spouts and shower-tub combinations. Current mixing valves provide a valve control member that regulates the temperature of the water. During use, the mixing valve can be rotated by the user from an off position through cold water, mixed water and hot water positions. The rotational position of the valve control member determines how much hot or cold water comprises the water outlet stream.
Mixing valves generally provide for either all cold water or all hot water streams without difficulty. During operation, a cold stream is easily obtained by incrementally rotating the mixing valve from an off position until a cold water stream is obtained. Similarly a hot water stream is easily obtained by fully rotating the mixing valve until the mixing valve can no longer rotate. However, most water users favor a mixed temperature outlet stream which is less tractable to obtain.
To begin with, the water user must manipulate the mixing valve using the faucet handle or knob until he obtains the desired combination of hot and cold water in the resulting water stream. Obtaining just the right temperature is difficult because the desired mixed temperature range position is very narrow resulting in substantial temperature changes in even an incremental rotational movement. If the user does not rotate enough, the water is still too cold, but if the user rotates too much the resulting hot water stream can injure or blister the skin of the water user. Even where no injury occurs, sudden changes in temperature of any kind are inconsistent with comfortable and soothing shower experience desired by users. Thus, there is a need for a mixing valve which provides a smoother and more gradual temperature transition between the hot and cold positions in order to give the user greater control in obtaining a mixed water stream and to minimize the possibility of the user's exposure to temperature extremes.
There is also a tendency for mixing valves to cause stacking. Stacking occurs where the water comes out of the showerhead while trying to use the tub spout and is caused when the hot and cold water form a vortex at the juncture between the tub port and shower bypass causing the pressure to increase at the shower bypass. When the pressure is high enough, the water will flow into the shower bypass and upwards to the showerhead. Thus, there is a need for a mixing valve which eliminates stacking by minimizing the pressure accumulation at the shower bypass.
Another drawback of current mixing valves is the noticeable difference in flow rates between the full cold water, mixed water and full hot water outlet streams. This difference may be particularly apparent between the mixed water and full hot water streams. Generally speaking, users desire high flow rates and thus high water pressure in the outlet stream because this helps the user rinse out soap and shampoo in less time than lower flow rates and water pressures. So, noticeable decreases in the flow rate and thus the water pressure represents an undesirable change to the user. It would therefore be beneficial to provide a mixing valve which minimizes the differences in flow rates between the outlet streams.
The present invention provides for a mixing valve having a gradual temperature transition through the use of tapered hot or cold water outlets within the mixing valve assembly. It also provides smoother fluid passageways to increase flow through the valve and eliminates stacking. The present invention further provides for increased corrosion resistence.